1. Field of the Invention
The present invention relates to an optical device having a periodically poled structure (hereinafter referred to simply as the “optical device”), a method of manufacturing the optical device and an exposure apparatus which uses the optical device.
2. Description of the Related Art
Ferroelectric crystals of lithium niobate (LiNbO3), lithium tantalite (LiTaO3) and the like have been under consideration as liquid crystals to be applied to optical devices for controlling light modulation, wavelength conversion, etc. The Document 1 (H. Gnewuch et al “Nanosecond Response of Bragg Deflectors in Periodically Poled LiNbO3”, IEEE PHOTONICS TECHNOLOGY LETTERS, VOL. 10, NO. 12, DECEMBER 1998) for instance describes a Bragg-deflection type optical modulator using periodically poled ferroelectric crystals. Further, the Document 2 (Yoshihito Hirano, “Super-compact wavelength conversion green laser and laser TV”, Applied Physics, Vol. 78, No. 11 (2009)) for instance describes a wavelength conversion device using a periodically poled planar waveguide (MgO:LN (PPMgLN)).